Electrochemical sensors are commonly used to detect or measure the concentrations of in vivo analytes, such as glucose. Typically in such analyte sensing systems, an analyte (or a species derived from it) is electro-active and generates a detectable signal at an electrode in the sensor. This signal is then correlated with the presence or concentration of the analyte within a biological sample. In some conventional sensors, an enzyme is provided that reacts with the analyte to be measured, the byproduct of the reaction being qualified or quantified at the electrode. In one conventional glucose sensor, immobilized glucose oxidase catalyzes the oxidation of glucose to form hydrogen peroxide, which is then quantified by amperometric measurements (e.g. change in electrical current) through one or more electrodes.
In order to reduce the size of the sensors and/or increase their sensitivity and efficiency, electrochemical sensors can be patterned with multiple electrodes on both sides of the sensor. A variety of electrochemical sensors have also been developed to be multi-layered (e.g. double-sided), comprising multiple layers of electrodes and conductors interposed between multiple layers of dielectric materials. The electrochemical properties of multilayered sensors can be tailored by altering certain design parameters (e.g. number of internal layers, layer thickness, area under the electrodes). However, fabricating such sensors requires extra steps such as the patterning both/multiple sides of sensor elements. Consequently, fabricating such multilayer sensors requires complicated and costly processes including, for example, reiteratively layering multiple elements. In addition, multilayer sensors typically require the use of vias (vertical interception access) to establish vertical electrical connections between the different layers of conductors, elements which add to the cost and complexity of fabricating such sensors.
There is a need for cost-effective sensors that provide the size, sensitivity, and efficiency advantages of double-sided and multilayer sensors, as well as simplified manufacturing processes for fabricating such sensors.